As a result of the recent development in the robot industry, the introduction of autonomous moving robots such as guard robots and nursing-care robot has been expected. In general, a moving robot requires a map in which position information of obstacles and the like are indicated in order to perform autonomous navigation. A problem for a moving robot to autonomously perform map construction/self-localization in an unknown environment is called “SLAM (Simultaneously Localization And Mapping)”, and has been widely studied in the past.